Method of protecting molten metals.



- UNITED STATES PATENT oFFIoE.

WALTER S. ROCKEY AND HILLIA RY ELDBIDGE, OF NEW YORK, N. Y.

No Drawing.

To all whmn it may concern:

Be it known that we, WALTER S. Rooney and HILLIARY ELDRJDGE, citizens of the United States, and residents of New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Methods of Protecting Molten Metals, of which the following is a specification.

Our invention relates ,to the melting of metals and protecting same from rapid oxidation and volatilization, and further relates to the use of the said melted or molten metal to serve as a bath for the plating of iron and steel either in sheet or rod form, or for cast metal, and also relates to the joining or brazing of iron and steel -either in sheet or rod form, \or castings, and plating the same simultaneously.-

When metals such as copper and zinc are melted together to produce brass, and the heat is increased above a proper degree, the zinc rapidly oxidizes and also volatilizes. To prevent the volatilization and oxidation of metals of this character, we have discovered that we can use any of the fusible halogen salts of the metals, such as sodium, calcium or potassium, which halogen salts are of less specific gravity thanthat of brass, tin, zinc, lead and other metals usually used for .plating purposes or for casting, and since the halogen salts of potassium, calcium or sodium require a temperature of from 650 inclusive to 815 degrees centi rade to melt the same, and the metals whic are to be protected melt at a considerably less temperature and each of greater specin gravity, the halogen salts will float to the top and upon the surface of the molten metals forming a cover for same and preventing the oxygen in the air from acting on the surface of the metals and also prevents the volatilization of the same when they are heated to a temperature considerably above that at which they would normally become volatile. We have also discovered that when zinc and copper are to be fused together that by first reducing the halogen salts toa fluid condition and first adding the zinc which is immediately melted, that when copper is added to the molten zinc, the cop er is dissolved or melted in the zinc which affects the copper and causes it to melt at about or just above the temperature of the zinc, and

Specification of Letters Patent.

7 Application filed March 5, 1909. Serial No. 481,434.

Patented Dec. 14, 1909.

at a temperature considerably below that at this metal or metals so protected, as a bath in which we may dip iron or steel, either in cast, drawn or rolled condition, or in the form of a wire to plate the same with the metal. I

In carrying out our invention for the purpose of lating a metal, we proceed as follow's:l K e select a crucible of neutral material, such as graphite, and into this we first place a halogen salt of one of the metals, for instance, potassium chlorid in suflicientquantity that when melted it will cover the metal to be protected, after melting the chlorid, we then add the metal or metals which we desire to plate with, or which we may wish to use to withdraw from the crucible for the purpose of casting, such as zinc, and copper or tm, or a combination of metals such as zinc and cop er to form brass, and after this is meltedlt forms the bath on the surface of which floats the potassium chlorid. Iron or steel may now be immersed through the chlorid into the metal, which metal may be at a temperature sufficient to volatilize or oxidize the same if 1t were not protected by the chlorid, but whlch does not needto be at such a high temperature if it is desired to coat at a lower temperature. When the iron to be coated 1s passed through the chlorid, the chlond acts on the surface of the iron to remove. all

ease or oxid of iron, and places the iron in the best possible condition to receive a coating of the metal, and by reason of the metal being at a comparatively high temperature, it is more evenly and perfectly coated than would otherwise be the case. When the rod or any other form of iron or steel which is being coated is being withdrawn from the bath, the coated surface must pass through the coating of the chlorid which is floating on the surface of thebath,

and the chlorid ,c'oats'the metal on the rod and prevents the rapid 'yaporization or oxidation of the metal which forms the plating on the rod-or any other form of 11On or.

. steel, since it acts as an insulating material and prevents the air from striking the surof metallic halogen salts-heretofore de-' face of the freshly coated metal.

Also a further objectof our invention. is 'to use these fused metals or metallic alloys which are protected by. the fused covering scribed, as a combined brazing" and plating medium for iron or steel, in sheet, rod, tube or cast form'. To aid in our description of -this procedure, we will explain that we find in practice that the joinmgor brazing of iron or steel together by means of the aforesaid described metals or alloys are dependent and cannot be consummated without plating simultaneously. I To illustrate we will proceed to describe the joining or brazof a tube and the simultaneous platin thereof; we will take'asheet iron or stee tube formed. by what. is termed by sheet Y metal workers the double or lap seamed rocess commonly known as. a water lead.

, In place of usin' a single halogen salt metals are used as a baththe halogen salt performs the double functionvof protectin the 'bath and aISo-cleaningthe' metal an '45 protecting its stirfa'ce immediately after it" of metal, combined romids, iodids or chlorids, known as double chlorids,"ma'y be used. R will be seen from the-above that when the 1s plated from oxidation or vaporization.

It will also be seen that this coating can be used to protect molten metals-from contact wlth'the air and prevents the loss of heat and permits of the met'albeing'withdrawn at a temperature higher than-the normal .temperaturebf these metals would otherwise permit-of, intom'olds for casting purposes. I

Having: thus described; our invention,

'said chlorid.

what we claim as new and desire to secure by Letters Patent-is 1. The method of protecting molten metals consisting in first reducing a suitable halogen salt to a fluid condition by heat and then reducin a fluid condition by heat beneath the sur-* the metal to be protected to face of said halogen salts. 2. The method of lating -cast or malleable, conslsting 1n first reducing .iron or steel,

in a suitable crucible a suitable halogen salt to a fluid state by heat, then reducing below the surface of said salt themetal or metals to form a bath to a fluid condition by heat and protectin the same beneath the surfaceof the ha ogen salt and then immersing the metalto be plated first throughthe halogen's'alt into the said metal bath, and from the metal bath through the halogen salt to the atmosphere, substantially as setforth. e 3. The method of'protectmg moltenmetals consisting *in. first reducing a suitable chlorid to a fluid condition by heatandthen reducing'the metal to be protected to a fluid condition by heat beneath the surface of the 4:. The method 'of protecting molten metals consisting in first reducin chlorid of potassium to a fluid condition y heat and then reducing the metal to be protected to a fluid condition by heat beneath the surface of the said chloridof potassium.

5: The method of simultaneous plating Y and brazing of iron or steel, cast ormalleable, consisting in first reducing in a suitable face of said halogen salt, the metal or metals to form a bath to a fluid condition by heat and protecting same beneath the surface of the halogen salt then immersing the iron orsteel to be plated and brazed, first through the halogen salt into the said metal bathcrucible, a sultable halogen salt to a'fluid 'stateby heat, then reducing below the surand from the metal bath through the hal ogen salt to theatmosphere substantially as. 'set' forth.

Signed at New York in the county of New York and State of New York this 4th day I of-March D. 1909.

. WALTER s. nioeKnrtf HILLIARY ELDRIDGE Witnesses G. F. QUAOKI'NBUSm' RAUL: HERMAN; 

